Toronto-based Sustain Design Studio is responsible for producing high technology modular housing systems which feature impeccable design. The mobile mini homes by Sustain Design Studio are not classed as buildings. As they are less than 400 sq ft. in area, these units can be classified as ‘Park Model Trailers’ – or even as ‘Travel Trailers’ if they are designed to be completely off-grid – and do not require a building permit.